First offense == warning (with police response, handcuffs, etc).

Second offense == 24 hours in jail.

You need to not wreck someone's life for a first offense because if you put a relatively poor but otherwise law abiding person in jail for 30 days after the first offense you're going to destroy their life to the point where the only path for them in the future is crime. Scare them enough to the point where they realize "I don't want this life" but put them in a position where they can avoid it.